Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.80 and 1.103

version 1.80, 2015/01/17 13:04:01 version 1.103, 2016/12/19 21:48:53
Line 81  xenkernel and xentools.  We will refer o Line 81  xenkernel and xentools.  We will refer o
 but note that both packages must be installed together and must have  but note that both packages must be installed together and must have
 matching versions.  matching versions.
   
 xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3.  These no longer  xenkernel3 provides Xen 3.1.  This no longer receives security patches
 receive security patches and should not be used.  Xen 3.1 supports PCI  and should not be used.  It supports PCI passthrough, which is why
 passthrough.  Xen 3.1 supports non-PAE on i386.  people use it anyway. Xen 3.1 supports non-PAE on i386.
   
   xenkernel33 provides Xen 3.3.  This no longer receives security
   patches and should not be used.  Xen 3.3 supports non-PAE on i386.
   
 xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,  xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,
 but as of 2014-12 receives backported security patches.  It is a  but as of 2014-12 receives backported security patches.  There are no
 reasonable although trailing-edge choice.  good reasons to run this version.
   
   xenkernel42 provides Xen 4.2. This is no longer maintained by Xen, but
   as of 2014-12 receives backported security patches.  The only reason
   to run this is if you need to use xm instead of xl.
   
   xenkernel45 provides Xen 4.5.  This is new to pkgsrc as of 2015-01 and
   recommended for use as a conservative choice.
   
 xenkernel42 provides Xen 4.2.  This is maintained by Xen, but old as  xenkernel46 provides Xen 4.6.  TODO: Probably this is the recommended
 of 2014-12.  version.
   
   See also the [Xen Security Advisory page](http://xenbits.xen.org/xsa/).
   
 Ideally newer versions of Xen will be added to pkgsrc.  Ideally newer versions of Xen will be added to pkgsrc.
   
 Note that NetBSD support is called XEN3.  It works with 3.1 through  Note that NetBSD support is called XEN3.  It works with Xen 3 and Xen
 4.2 because the hypercall interface has been stable.  4 because the hypercall interface has been stable.
   
 Xen command program  Xen command program
 -------------------  -------------------
Line 125  Architecture Line 137  Architecture
 ------------  ------------
   
 Xen itself can run on i386 or amd64 machines.  (Practically, almost  Xen itself can run on i386 or amd64 machines.  (Practically, almost
 any computer where one would want to run Xen supports amd64.)  If  any computer where one would want to run Xen today supports amd64.)
 using an i386 NetBSD kernel for the dom0, PAE is required (PAE  
 versions are built by default).  While i386 dom0 works fine, amd64 is  Xen, the dom0 kernel, and each domU kernel can be either i386 or
 recommended as more normal.  amd64.  When building a xenkernel package, one obtains i386 on an i386
   host, and amd64 on an amd64 host.  If the xen kernel is i386, then the
   dom0 kernel and all domU kernels must be i386.  With an amd64 xen
   kernel, an amd64 dom0 kernel is known to work, and an i386 dom0 kernel
   should in theory work.  An amd64 xen/dom0 is known to support both
   i386 and amd64 domUs.
   
   i386 dom0 and domU kernels must be PAE (except for Xen 3.1); these are
   built by default.  (Note that emacs (at least) fails if run on i386
   with PAE when built without, and vice versa, presumably due to bugs in
   the undump code.)
   
   Because of the above, the standard approach is to use amd64 for the
   dom0.
   
 Xen 4.2 is the last version to support i386 as a host.  TODO: Clarify  Xen 4.2 is the last version to support i386 as a host.  TODO: Clarify
 if this is about the CPU having to be amd64, or about the dom0 kernel  if this is about the CPU, the xen kernel, or the dom0 kernel having to
 having to be amd64.  be amd64.
   
   
   Stability
   ---------
   
   Mostly, NetBSD as a dom0 or domU is quite stable.
   However, there are some open PRs indicating problems.
   
    - [PR 48125](http://gnats.netbsd.org/48125)
    - [PR 47720](http://gnats.netbsd.org/47720)
   
 One can then run i386 domUs and amd64 domUs, in any combination.  If  Note also that there are issues with sparse vnd(4) instances, but
 running an i386 NetBSD kernel as a domU, the PAE version is required.  these are not about Xen.
 (Note that emacs (at least) fails if run on i386 with PAE when built  
 without, and vice versa, presumably due to bugs in the undump code.)  
   
 Recommendation  Recommendation
 --------------  --------------
Line 211  dom0 is what the computer would have bee Line 244  dom0 is what the computer would have bee
 desktop or laptop.  Then, one can run domUs at will.  Purists will  desktop or laptop.  Then, one can run domUs at will.  Purists will
 deride this as less secure than the previous approach, and for a  deride this as less secure than the previous approach, and for a
 computer whose purpose is to run domUs, they are right.  But Xen and a  computer whose purpose is to run domUs, they are right.  But Xen and a
 dom0 (without domUs) is not meaingfully less secure than the same  dom0 (without domUs) is not meaningfully less secure than the same
 things running without Xen.  One can boot Xen or boot regular NetBSD  things running without Xen.  One can boot Xen or boot regular NetBSD
 alternately with little problems, simply refraining from starting the  alternately with little problems, simply refraining from starting the
 Xen daemons when not running Xen.  Xen daemons when not running Xen.
Line 236  over a RAID1 header to find /boot from a Line 269  over a RAID1 header to find /boot from a
 partition; this is no different when booting Xen.  partition; this is no different when booting Xen.
   
 There are 4 styles of providing backing storage for the virtual disks  There are 4 styles of providing backing storage for the virtual disks
 used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,  used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN.
   
 With raw partitions, one has a disklabel (or gpt) partition sized for  With raw partitions, one has a disklabel (or gpt) partition sized for
 each virtual disk to be used by the domU.  (If you are able to predict  each virtual disk to be used by the domU.  (If you are able to predict
Line 309  starting at 0).  In an attempt to add pe Line 342  starting at 0).  In an attempt to add pe
 to force only one vcpu to be provided (since NetBSD dom0 can't use  to force only one vcpu to be provided (since NetBSD dom0 can't use
 more) and to pin that vcpu to a physical cpu.  TODO: benchmark this.  more) and to pin that vcpu to a physical cpu.  TODO: benchmark this.
   
   Xen has [many boot
   options](http://xenbits.xenproject.org/docs/4.5-testing/misc/xen-command-line.html),
   and other tham dom0 memory and max_vcpus, they are generally not
   necessary.
   
 As with non-Xen systems, you should have a line to boot /netbsd (a  As with non-Xen systems, you should have a line to boot /netbsd (a
 kernel that works without Xen) and fallback versions of the non-Xen  kernel that works without Xen) and fallback versions of the non-Xen
 kernel, Xen, and the dom0 kernel.  kernel, Xen, and the dom0 kernel.
Line 337  Xen logs will be in /var/log/xen. Line 375  Xen logs will be in /var/log/xen.
 Now, you have a system that will boot Xen and the dom0 kernel, but not  Now, you have a system that will boot Xen and the dom0 kernel, but not
 do anything else special.  Make sure that you have rebooted into Xen.  do anything else special.  Make sure that you have rebooted into Xen.
 There will be no domUs, and none can be started because you still have  There will be no domUs, and none can be started because you still have
 to configure the dom0 tools.  The daemons which should be run vary  to configure the dom0 daemons.
 with Xen version and with whether one is using xm or xl.  Note that  
 xend is for supporting "xm", and should only be used if you plan on  
 using "xm".  Do NOT enable xend if you plan on using "xl" as it will  
 cause problems.  
   
 The installation of NetBSD should already have created devices for xen  
 (xencons, xenevt), but if they are not present, create them:  
   
         cd /dev && sh MAKEDEV xen  
   
 TODO: Give 3.1 advice (or remove it from pkgsrc).  The daemons which should be run vary with Xen version and with whether
   one is using xm or xl.  The Xen 3.1 and 3.3 packages use xm.  Xen 4.1
   and higher packages use xl.  While is is possible to use xm with some
   4.x versions (TODO: 4.1 and 4.2?), the pkgsrc-provided rc.d scripts do
   not support this as of 2014-12-26, and thus the HOWTO does not support
   it either.  (Make sure your packages are reasonably recent.)
   
 For 3.3 (and thus xm), add to rc.conf (but note that you should have  For "xm" (3.1 and 3.3), you should enable xend and xenbackendd (but
 installed 4.1 or 4.2):  note that you should be using 4.x):
   
         xend=YES          xend=YES
         xenbackendd=YES          xenbackendd=YES
   
 For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:  For "xl" (4.x), you should enabled xend and xencommons (xenstored).
   Trying to boot 4.x without xencommons=YES will result in a hang; it is
   necessary to hig ^C on the console to let the machine finish booting.
   TODO: explain why xend is installed by the package.
   
         xencommons=YES          xencommons=YES
         xend=YES  
   
 (If you are using xentools41 from before 2014-12-26, change  
 rc.d/xendomains to use xm rather than xl.)  
   
 For 4.2 with xm, add to rc.conf  
   
         xencommons=YES  The installation of NetBSD should already have created devices for xen
         xend=YES  (xencons, xenevt), but if they are not present, create them:
   
 For 4.2 with xl, add to rc.conf:  
   
         xencommons=YES          cd /dev && sh MAKEDEV xen
         TODO: explain if there is a xend replacement  
   
 TODO: Recommend for/against xen-watchdog.  TODO: Recommend for/against xen-watchdog.
   
 After you have configured the daemons and either started them (in the  After you have configured the daemons and either started them (in the
 order given) or rebooted, use xm or xl to inspect Xen's boot messages,  order given) or rebooted, use xm or xl to inspect Xen's boot messages,
 available resources, and running domains.  An example with xm follows:  available resources, and running domains.  An example with xl follows:
   
         # xm dmesg          # xl dmesg
         [xen's boot info]          [xen's boot info]
         # xm info          # xl info
         [available memory, etc.]          [available memory, etc.]
         # xm list          # xl list
         Name              Id  Mem(MB)  CPU  State  Time(s)  Console          Name              Id  Mem(MB)  CPU  State  Time(s)  Console
         Domain-0           0       64    0  r----     58.1          Domain-0           0       64    0  r----     58.1
   
 With xl, the commands are the same, and the output may be slightly  ### Issues with xencommons
 different.  TODO: add example output for xl, after confirming on 4.2  
 and resolving the TODO about rc.conf.  xencommons starts xenstored, which stores data on behalf of dom0 and
   domUs.  It does not currently work to stop and start xenstored.
   Certainly all domUs should be shutdown first, following the sort order
   of the rc.d scripts.  However, the dom0 sets up state with xenstored,
   and is not notified when xenstored exits, leading to not recreating
   the state when the new xenstored starts.  Until there's a mechanism to
   make this work, one should not expect to be able to restart xenstored
   (and thus xencommons).  There is currently no reason to expect that
   this will get fixed any time soon.
   
 anita (for testing NetBSD)  anita (for testing NetBSD)
 --------------------------  --------------------------
   
 With the setup so far, one should be able to run anita (see  With the setup so far (assuming 4.2/xl), one should be able to run
 pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as root,  anita (see pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as
 because anita must create a domU):  root, because anita must create a domU):
   
         anita --vmm=xm test file:///usr/obj/i386/          anita --vmm=xl test file:///usr/obj/i386/
   
 Alternatively, one can use --vmm=xl to use xl-based domU creation instead.  Alternatively, one can use --vmm=xm to use xm-based domU creation
 TODO: check this, and make the example use xl when confirmed.  instead (and must, on Xen <= 4.1).   TODO: confirm that anita xl really works.
       
 Xen-specific NetBSD issues  Xen-specific NetBSD issues
 --------------------------  --------------------------
   
Line 464  section. Line 500  section.
   
 TODO: actually do this and fix it if necessary.  TODO: actually do this and fix it if necessary.
   
 Updating Xen versions  Upgrading Xen versions
 ---------------------  ---------------------
   
 Updating Xen is conceptually not difficult, but can run into all the  Updating Xen is conceptually not difficult, but can run into all the
Line 472  issues found when installing Xen.  Assum Line 508  issues found when installing Xen.  Assum
 remove the xenkernel41 and xentools41 packages and install the  remove the xenkernel41 and xentools41 packages and install the
 xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.  xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
   
 Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the  Ensure that the contents of /etc/rc.d/xen* are correct.  Specifically,
 correct set of daemons.  Ensure that the domU config files are valid  they must match the package you just installed and not be left over
 for the new version.  from some previous installation.
   
   Enable the correct set of daemons; see the configuring section above.
   (Upgrading from 3.x to 4.x without doing this will result in a hang.)
   
   Ensure that the domU config files are valid for the new version.
   Specifically: remove autorestart=True, and ensure that disks are
   specified with numbers as the second argument, as the examples above
   show, and not NetBSD device names.
   
   Hardware known to work
   ----------------------
   
   Arguably, this section is misplaced, and there should be a page of
   hardware that runs NetBSD/amd64 well, with the mostly-well-founded
   assumption that NetBSD/xen runs fine on any modern hardware that
   NetBSD/amd64 runs well on.  Until then, we give motherboard/CPU/RAM
   triples to aid those choosing a motherboard.  Note that Xen systems
   usually do not run X, so a listing here does not imply that X works at
   all.
   
           Supermicro X9SRL-F, Xeon E5-1650 v2, 96 GiB ECC
           Supermicro ??, Atom C2758 (8 core), 32 GiB ECC
           ASUS M5A78L-M/USB3 AM3+ microATX, AMD Piledriver X8 4000MHz, 16 GiB ECC
   
   Older hardware:
   
           Intel D915GEV, Pentium4 CPU 3.40GHz, 4GB 533MHz Synchronous DDR2
   
   Running Xen under qemu
   ----------------------
   
   The astute reader will note that this section is somewhat twisted.
   However, it can be useful to run Xen under qemu either because the
   version of NetBSD as a dom0 does not run on the hardware in use, or to
   generate automated test cases involving Xen.
   
   In 2015-01, the following combination was reported to mostly work:
   
           host OS: NetBSD/amd64 6.1.4
           qemu: 2.2.0 from pkgsrc
           Xen kernel: xenkernel42-4.2.5nb1 from pkgsrc
           dom0 kernel: NetBSD/amd64 6.1.5
           Xen tools: xentools42-4.2.5 from pkgsrc
   
   See [PR 47720](http://gnats.netbsd.org/47720) for a problem with dom0
   shutdown.
   
 Unprivileged domains (domU)  Unprivileged domains (domU)
 ===========================  ===========================
Line 537  domain, and see if it has finished stopp Line 618  domain, and see if it has finished stopp
         xm console foo          xm console foo
         xm create -c foo          xm create -c foo
         xm shutdown foo          xm shutdown foo
         xm list          xm list
   
 Typing ^] will exit the console session.  Shutting down a domain is  Typing ^] will exit the console session.  Shutting down a domain is
 equivalent to pushing the power button; a NetBSD domU will receive a  equivalent to pushing the power button; a NetBSD domU will receive a
Line 597  create an empty 4G virtual disk, simply  Line 678  create an empty 4G virtual disk, simply 
   
         dd if=/dev/zero of=foo-xbd0 bs=1m count=4096          dd if=/dev/zero of=foo-xbd0 bs=1m count=4096
   
   Do not use qemu-img-xen, because this will create sparse file.  There
   have been recent (2015) reports of sparse vnd(4) devices causing
   lockups, but there is apparently no PR.
   
 With the lvm style, one creates logical devices.  They are then used  With the lvm style, one creates logical devices.  They are then used
 similarly to vnds.  TODO: Add an example with lvm.  similarly to vnds.  TODO: Add an example with lvm.
   
Line 674  shutdown, in rc.conf add: Line 759  shutdown, in rc.conf add:
   
         xendomains="foo bar"          xendomains="foo bar"
   
 TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm  Note that earlier versions of the xentools41 xendomains rc.d scripth
 on 4.1.  Or fix the xentools41 package to have xm  usd xl, when one should use xm with 4.1.
   
 Creating specific unprivileged domains (domU)  Creating specific unprivileged domains (domU)
 =============================================  =============================================
Line 700  i386 and amd64 provide the following ker Line 785  i386 and amd64 provide the following ker
   
         i386 XEN3_DOMU          i386 XEN3_DOMU
         i386 XEN3PAE_DOMU          i386 XEN3PAE_DOMU
         amd64 XEN3_DOMU          amd64 XEN3_DOMU
   
 Unless using Xen 3.1 (and you shouldn't) with i386-mode Xen, you must  Unless using Xen 3.1 (and you shouldn't) with i386-mode Xen, you must
 use the PAE version of the i386 kernel.  use the PAE version of the i386 kernel.
Line 753  It is also desirable to add Line 838  It is also desirable to add
 in rc.conf. This way, the domain will be properly shut down if  in rc.conf. This way, the domain will be properly shut down if
 `xm shutdown -R` or `xm shutdown -H` is used on the dom0.  `xm shutdown -R` or `xm shutdown -H` is used on the dom0.
   
 Your domain should be now ready to work, enjoy.  It is not strictly necessary to have a kernel (as /netbsd) in the domU
   filesystem.  However, various programs (e.g. netstat) will use that
   kernel to look up symbols to read from kernel virtual memory.  If
   /netbsd is not the running kernel, those lookups will fail.  (This is
   not really a Xen-specific issue, but because the domU kernel is
   obtained from the dom0, it is far more likely to be out of sync or
   missing with Xen.)
   
 Creating an unprivileged Linux domain (domU)  Creating an unprivileged Linux domain (domU)
 --------------------------------------------  --------------------------------------------
Line 941  to update the special boot partiion. Line 1032  to update the special boot partiion.
 Amazon  Amazon
 ------  ------
   
 TODO: add link to NetBSD amazon howto.  See the [Amazon EC2 page](../amazon_ec2/).
   
 Using npf  Using npf
 ---------  ---------
   
 In standard kernels, npf is a module, and thus cannot be loadeed in a  In standard kernels, npf is a module, and thus cannot be loaded in a
 DOMU kernel.  DOMU kernel.
   
 TODO: explain how to compile npf into a custom kernel, answering (but  TODO: Explain how to compile npf into a custom kernel, answering (but
 note that the problem was caused by not booting the right kernel):  note that the problem was caused by not booting the right kernel)
 http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html  [this email to
   netbsd-users](http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html).
   
 TODO items for improving NetBSD/xen  TODO items for improving NetBSD/xen
 ===================================  ===================================
   
 * Package Xen 4.4.  * Make the NetBSD dom0 kernel work with SMP.
 * Get PCI passthrough working on Xen 4.2 (or 4.4).  * Test the Xen 4.5 packages adequately to be able to recommend them as
     the standard approach.
   * Get PCI passthrough working on Xen 4.5
 * Get pvgrub into pkgsrc, either via xentools or separately.  * Get pvgrub into pkgsrc, either via xentools or separately.
 * grub  * grub
   * Check/add support to pkgsrc grub2 for UFS2 and arbitrary    * Check/add support to pkgsrc grub2 for UFS2 and arbitrary
Line 969  TODO items for improving NetBSD/xen Line 1063  TODO items for improving NetBSD/xen
   * Get UFS2 patches into pvgrub.    * Get UFS2 patches into pvgrub.
 * Add support for PV ops to a version of /boot, and make it usable as  * Add support for PV ops to a version of /boot, and make it usable as
   a kernel in Xen, similar to pvgrub.    a kernel in Xen, similar to pvgrub.
   * Solve somehow the issue with modules for GENERIC not being loadable
     in a Xen dom0 or domU kernel.
   
   Random pointers
   ===============
   
   TODO: This section contains links from elsewhere not yet integrated
   into the HOWTO.
   
   * http://www.lumbercartel.ca/library/xen/
   * http://pbraun.nethence.com/doc/sysutils/xen_netbsd_dom0.html

Removed from v.1.80  
changed lines
  Added in v.1.103


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